# Topic 3.1 : Forces

Topic 3.1 : Forces
Learning goals:
• I can explain what a force is and can identify different types of
forces.
• I can calculate the gravitational force acting on an object.
• I can draw arrows on a force diagram,
with the correct point of
application, magnitude and direction.
• I can calculate the resultant force of forces going
in the same
direction or opposite directions of each other.
• VWO ONLY - I can calculate the resultant force
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Slide 1: Tekstslide
ScienceMiddelbare schoolhavoLeerjaar 2

In deze les zitten 25 slides, met interactieve quizzen en tekstslides.

## Onderdelen in deze les

Topic 3.1 : Forces
Learning goals:
• I can explain what a force is and can identify different types of
forces.
• I can calculate the gravitational force acting on an object.
• I can draw arrows on a force diagram,
with the correct point of
application, magnitude and direction.
• I can calculate the resultant force of forces going
in the same
direction or opposite directions of each other.
• VWO ONLY - I can calculate the resultant force

#### Slide 1 -Tekstslide

Topic 3.1 : Forces
Forces are all around us, You can’t see them !
You can only see their effect

Object changes shape
Object starts to move
Object changes speed
Direction of object changes

#### Slide 2 -Tekstslide

Topic 3.1 : Forces
Object changes shape

#### Slide 3 -Tekstslide

Topic 3.1 : Forces
Object starts to move

#### Slide 4 -Tekstslide

Topic 3.1 : Forces
Object changes speed

#### Slide 5 -Tekstslide

Topic 3.1 : Forces
Object changes direction

#### Slide 6 -Tekstslide

Topic 3.1: Forces
There are many types of forces
Types of forces
Unit
Also known as
Gravity
Fg
Applied force
Fa
muscle force
Air resistance
Fair
drag
Friction
Ff
Tension force
Ft
Spring force
Fs
elastic force
Normal force
Fn
support force
Topic 3.1:
Forces

#### Slide 7 -Tekstslide

Air resistance force
Gravity force
Spring force
magnetic force

Normal Force
Tension Force
applied force
Friction force

#### Slide 8 -Sleepvraag

Topic 3.1: Forces
Force (F)
Measured in Newtons (N)

The force needed to lift 1 kg = 9.8 N on earth
On the moon the force needed is only 1.6 N
The mass is the same
Gravitational force is different

#### Slide 9 -Tekstslide

Topic 3.1: Forces
Formula for calculating Gravity force

Fg is the gravitational force in [N]
m is the mass in [kg]
9.8 is the gravitational constant on earth in N / kg or
Fg = m x 9.8
m / s2

#### Slide 10 -Tekstslide

Topic 3.1: Forces
Example:
The mass of Peter is 76 kg. What is his gravitational force, Fg?

Fg                        = m x 9.8
Fg = 76 [kg] x 9.8 [N/kg]
Fg                      = 744.8 [N]

#### Slide 11 -Tekstslide

The mass of Mohamed is 45 kg. What is his gravitational force, Fg
A
350 N
B
45 N
C
441 N
D
882 N

#### Slide 12 -Quizvraag

The gravitational force of my cat is 34.3N What is her mass?
A
34,3 kg
B
3,5 kg
C
336 kg
D
24,5 kg

#### Slide 13 -Quizvraag

Topic 3.1 : Forces
Forces are represented by an arrow

It has three things:

1. point of application (origin of force)
2. direction
3. magnitude (the longer the arrow, the bigger the force)

#### Slide 14 -Tekstslide

Topic 3.1: Forces
1. point of origin:
Centre of mass

2. Direction:
downward

3. Magnitude:
depending on scale

#### Slide 15 -Tekstslide

Name types of forces

#### Slide 16 -Woordweb

A forces is drawn with a length of 4 cm
The scale is 1 cm = 30 N
What is the magnitude of the force drawn?
A
60 N
B
30 N
C
120 N
D
7,5 N

#### Slide 17 -Quizvraag

I want to draw a force with a magnitude of 300 N.
The scale must be 1 cm = 60 N
How large should the arrow (vector) be?
A
2 cm
B
5 cm
C
10 cm
D
12 cm

#### Slide 18 -Quizvraag

Topic 3.1: Forces

Two forces in the same direction are added up

Two forces in opposite direction are subtracted from eachother

If forces are equal and in opposite direction, there is no motion!

#### Slide 19 -Tekstslide

What is the resultant force?
A
140 N to the left
B
140 N to the right
C
60 N to the left
D
60 N to the right

#### Slide 20 -Quizvraag

What is the resultant force?
A
225 N to the left
B
225 N to the right
C
25 N to the left
D
25 N to the right

#### Slide 21 -Quizvraag

Topic 3.1: Forces
Adding up forces that are not in one line

begin to end = resultant force

#### Slide 22 -Tekstslide

Forces can't be seen.
What effects of a force can be seen?
A
changes in shape
B
changes in temperature
C
changes is color
D
changes in density

#### Slide 23 -Quizvraag

A person on earth has a mass of 80 kg. What is the gravitational force?

#### Slide 24 -Open vraag

Topic 3.1 : Forces
Learning goals:
• I can explain what a force is and can identify different types of
forces.
• I can calculate the gravitational force acting on an object.
• I can draw arrows on a force diagram,
with the correct point of
application, magnitude and direction.
• I can calculate the resultant force of forces going
in the same
direction or opposite directions of each other.
• VWO ONLY - I can calculate the resultant force